WASHINGTON — Rep. John Mica, who once brought a fake joint to a hearing, held another congressional investigation Thursday into the dangers of marijuana, but this time came bearing a new prop.

The Florida Republican hoisted a pot “testing machine” that he said is deployed in Europe and demanded federal regulators make similar technology available in the US.

With more states approving legal pot, Micam said he’s concerned that more drivers will be high on the highways without police having the equipment to test them.

“We have no acceptable test,” Mica told federal regulators Thursday as he held up a device resembling a giant-size TV remote. “And we have no way of telling if people are impaired.”

But his Democratic counterpart, Rep. Gerry Connolly of Virginia, said Mica is in a rush to conclusions.

Connolly got one federal regulator to say there’s no clear estimate on how many crashes are caused by pot and not enough science to determine what THC chemical level is too much for driving, similar to the .08 percent limit for alcohol.

“I think it’s amazing with some of the hyperventilative rhetoric about marijuana use and THC, that 50 years after we’ve declared it a Class 1 substance we still don’t have enough data to know just how dangerous it is in operating a vehicle,” Connolly said.

THC is the chemical in pot that makes users high.

Mica has held several hearings on pot as some 23 states have moved to legalize it for medical purposes — and in a couple of instances for recreational use.

Mica called Thursday’s House Government Oversight subcommittee hearing: “Planes, Trains and Automobiles, Operating While Stoned.” He opened the panel displaying dramatic pictures of crashes.

“We are going to have a lot more people stoned on the highway and there will be consequences,” Mica said.

Jeff Michael, an administrator at the National Highway Traffic and Safety Administration, said the federal government is collecting more data on the risk of pot-related crashes and pot’s prevalence.

Those pot-testers Mica heralded are indeed being deployed in California in a pilot program, Michael said.

“Much more research is needed to gain a good understanding of the effects of drugs other than alcohol on safe driving,” Michael said.

In the absence of data, Connolly said he understands why so many states have moved to legalize pot and he questioned why the US government still considers it a dangerous drug.

The lack of evidence “raises serious questions about how our government is operating in terms of the data it does not have and the science it does not know, yet the assertions that we make,” Connolly said.